Transformer



P 25, 1951 H. J. BENNER ET AL 2,569,036

TRANSFORMER Filed Dec. 28, 1946 2 Sheets-Sheet l INVENTOR HOWARD J. BENNER ALLAN M. HADLEY p 1951 l H. J. BENNER ET AL 2,569,036

TRANSFORMER Filed Dec. 28, 1946 2 Sheets-Sheet 2 wlllllll llllllil INVENTOR HOWARD J. BENNER '5 LLAN M. HADLEY by 212 Patented Sept. 25, 1951 TRANSFORMER Howard J.1 Benners and Allan Ma Hadley,'.Long- .meadow, .Mass., assignors,;xby mesneassiflnments, to General Instruments Corporation, Elizabeth, N. J a corporation of New Jersey Application December 28, 1946,- Serial No. 719,042

17 Claims.

. Thisxinvention: relates: :to In a: novel transformer assembly particularly adapted. for use in. radio and television:receiverszand.transmitters.

- Size, weight.and costxofeelectrical :units used in. radio and other :communication. sets. are: of primeimportance. vI'I he-trend toward smaller receiving andItransmittingsetS,.both in military, industrial and. home applications has brought with it anattendantxdemand for smallerelectricalunits. Since these small sets are inmost cases designed to be 'portabla -weight becomes an. important-factor. As. elements inithe cost,.always significant: commercial-wise are-the amount and typesof material usedand the labor involved: in assembly.

It is theprime object'of. the present invention to devise a-transformer assembly for use in: communication sets' of the type. described which. is smaller thanpreviously known. units. serving. a similar purpose and which achieves this reduction in size without loss ofxefiiciencyonfidelity of transformer action.

IlI-iiSYCtLaIIOthBr-ObjECt of the: present invention to. devise sucham assembly which .is of. considerably lighterrweight and atithe same time "is much sturdier than. thosepreviou'sly known.

'Pstill zanother object of the. present .invention is 'to "devise sucln an: assembly the component parts: of which ..may. be-' easily fabricated. by :mass production methods and may be conveniently and rapidly assembled-.2 with an attendant'decreaseiin production costs.

:rAnother object of the present invention isto provide a:cmpact:. transformer assembly. comprising a pair of resonant circuits each including a condenser and an-inductance, the degree of coupling between said circuits. being adjustable-during assembly and the tuning of eachof said circuits beingindividuallyadjustable at will after assembly.

It is'a further object of the. present: invention to. provide such an assembly to which additional circuit elements, such as resistors, fixed capacitors, or diode filter-assemblies, may be .attached without-anyincrease in the. space taken up bysuch assemblies, thus. markedly increasing the flexibilityof use of such. an. assembly.

. A more. specific object of ..the present invention is to provide amore convenientmethod for electrically connecting the free ends of the coils of theinductances-to their respective condensers, thisv means being. particularlyadapted .to high speed industrial assembly operations.

To-the accomplishment of the foregoingiobjects and. such other objects as may hereinafter .ap-

pear, .the... presentvinvention relates to an inter mediate frequency transformer assembly and to a coil-core combination 1. particularly adapted for gether with athe .-.accompanying drawing n,

which 1 Fig. Lisa side elevational view of a transformer assembly;

Fig. 2. is a..similar-view takenrafter the. assembly has. been rotated aboutqits longitudinal axis;

Fig. 3 is a top view thereof;

Fig. .4 .is a; bottomwiewthereof;

Fig. 5. .is a view corresponding to Fig. 1. but of the main frameof. the assembly. alone;

Fig. 6 is. a cross-sectional view. taken along the linev 6+6. of. Fig.5;

.Fig- 7 is a cross-sectional view ofthecoil-core assembly employed with. {this transformer;

. Fig. 8. isla side view. .ofan auxiliary. terminal particularly .adapted for :use. with this. assembly ,Fig. 9 is..a view. similar to.-Fi ..8 but. showing the auxiliary terminal. after it has. been. rotated 90 about-its vertical axis;

Fig.v 10 is a view corresponding. to Fig. 4 but showing the. auxiliary terminal in place; 7

Fig. llzis a view corresponding to Fi ..l showing one mode of employment of said auxiliary terminal, a filter unit-being: incorporatedinto the assembly;

Fig. 12 isabottom viewof Fig. 11; p I I Fig. 18 is a schematic representation of. the circuit formedby the connectionsvofFig. 11; and

Figs. 14 and '15- are views-corresponding-.to Figs. 8 and 9 of an alternative embodiment of the aux iliary terminal.

Transformers, and intermediate frequency transformers in particulannavein the past employed a pair of .coilsspacedone from the other and wound onahollowshell of insulating material such as paperto one end of which is attached a support carrying a pair of adjustable condensers,. and suitable electrical connectionsare made betweenthe condensers and the coils so. as tov define aapair ofinductlvely related resonant circuits. In. order .to increasethe magneticv .effect of thecoils, cores-of.magnetidmaterial are often placed inside thepaper. shelland in many cases theposition of .these coresmaybemanually adjusted .to tune .the. respective. circuits. These assemblies, because. ofthecircuit requirements of. resonantlfrequencyand coupling imposed by the .communicationsets inwhich they are used, are, when. compared with. the. radio transformers employed early in the development of radio, of relatively small size. They are, however, somewhat fragile and present considerable assembly difiiculties from a production point of view. The transformer construction which we have invented is not only considerably sturdier and smaller than those of the prior art but is also more adapted to mass production in that its various component parts may be separately fabricated and easily assembled, the electrical connections to form the requisite resonant circuits being exceedingly easy to make.

The transformer assemblyof the present invention comprises a main frame, generally designated A, which is formed of a non-conductive material, and preferably of a non-conductive moldable plastic such as polystyrene. By employing such a material, the main frame A may be easily fabricated at low cost into its unusual shape consisting of at least two parallel legs B and C joined at one end by a cross-piece D so as to define therebetween an open ended passage E. The coils F, F are wound in peripheral grooves on cores G, G, the cores G, G being secured within the passage E by frictional or adhesive positive contact with the legs B and C. By means of this construction, the main frame A and cores G, G may be separately formed, the coils F, F may be wound ontheir respective cores G, G unimpeded by the presence of any other structure or apparatus and the units may then be assembled rapidly and efficiently. a

To the top of the cross-piece D is preferably attached a support H carrying one or more condensers J, J. As here illustrated, the support H is separate from the main frame A but it may, of course, be formed simultaneously therewith and as an integral part thereof, particularly should a moldable plastic be employed. Conductive strips K are provided to define the electrical connections between the condensers J, J and their respective coils F, F. Feet L, L fastened in any suitable manner, as by adhesive or heat sealing, to the ends of the legs B and C opposite from the cross-piece D, or molded integrally therewith, serve to position the free ends of the strips K so as to form a more rigid structure.

In order to decrease the size of the transformer assembly and at the same time maintain unimpaired its electrical properties the cores G and G are preferably formed of magnetic material such as powdered iron and a peripheral groove 2 to accommodate the coil F is formed therein preferably as part of the molding or formation of the core G itself. However, the core G may first be cylindrically shaped and the peripheral groove 2 may then be cut therefrom. In those special applications where the electrical and magnetic requirements of the transformer so dictate, the cores G may, of course, be formed of any suitable material such as non-magnetic polystyrene or conductive brass. In the latter case, the coils F and F must of course be suitably insulated from the cores G. By forming the core G of high grade iron such as that put out under the designation GlF by the Stackpole Carbon 00., random winding of the coil F may be employed and the coil may be formed of wire of very small diameter while attaining Qs (the measure of efficiency of a coil) on the order of 75 to 80 when the transformer is tuned to the customary radio intermediate frequency of 455 kc. and Qs as high as 100 are regularly obtained 4 when the circuits in which the coils are employed are tuned to the considerably higher intermediate frequency employed in frequency modulation reception. Since the coil F is substantially entirely received within the peripheral groove 2, it will be apparent that contact between the parallel legs B and C and the core G will be made along the outer surfaces A and 6 of the large diameter portions of the core G. It will thus be apparent that the coils F may be wound on their cores G quickly and efliciently, no special precautions as to manner of winding being necessary, and the cores G carryingtheir coils F may then be inserted through the open end of the passage E between the legs B and C, there to be retained.

The degree of coupling between the two coils F and F may be varied in assembly by adjusting the displacement between the cores G and G within the passage E. While it is feasible to wind the coils F and F in separate peripheral grooves 2 on the same magnetic core, and while this may be desirable in certain applications, when applied to some radio applications it has been found that to attain the requisite degree of decoupling, .a core of inordinate length must be employed, thus giving rise to a transformer assembly of excessive size. By forming an air gap between the separate cores G and G, the length of which is variable at ,will during assembly, and which need be .only of nominal length, it has been found that transformer size may be minimized and at the same time the proper degree of decoupling between the coils F and F may also be achieved. The intermagnetic effects of the transformer may also be controlled by insertingbetween the cores G and G a spacer of any desired dielectric material.

While the frictional contact between the interior faces 8 and H) of the legs B and C with the outer surfaces 4 and 6 of. the cores G and G may be sufficient to retain the cores. G and G in their proper positions, it has been found desirable in order to ensure that the cores G and G will not move from their adjusted position to undesirably vary the couplin between the coils F and F after the unit has been assembled, that the legs B and C be deformed so as to define tabs I2, these tabs contacting the end surfaces l4 and 16 of the cores G and G to positively maintain them in their position within the passage E. When the main frame A is formed of polystyrene or any similar plastic material, this deformation can be easily accomplished by the use of heat and pressure. Any suitable adhesive may also be employed in lieu of or in addition to the above-mentioned fastening methods to fix the position of the cores G and G in the passage E.

In order to further facilitate the insertion and retention of the cores G within the passage E, the interior surfaces 8 and ID of the legs B and C may be spherically curved as illustrated in Fig. 6 and the surfaces 4 and 6 of the cores G and G may be similarly curved.

The assembly as thus far described provides a structural assembly well suited for the manufacture of transformers of all sizes and types. In the specific application of intermediate frequency transformers for radio receiving and transmitting sets, it has been found desirable to incorporate with each of the coils F and F a condenser J and J so that each coil and condenser combination will define a parallel resonant circuit. It has also been found desirable that such a circuit be capable, after installation,

of-being tuned to a desired frequency. In ormer to accommodate the construction 1 thus-described to this application, the top 'of the cross-piece D is provided with a projection l8 adapted to fit within a recess 20 in the-support H, the latter I "denserplates has, preferably formingan integral F;

'part' thereof, a condenser terminal whichprojects downwardly through-a suitable aperture'in the'support H so as'toprojectfrom'the support toward the main frame A. To facilitateconheating the free ends 26,? of either of the coils "F, F to the terminals of the appropriate confidensers J, J, conductive strips "K are employed "the upper ends 28 of which are fixedly and electrically connected to the'appropriate condenser terminals 24. To facilitate this 'connectiomthe "condenser terminals 24 may be "slotted as at 30 "and bent inwardly at 3| (see Fig. 1) and the upper ends 28 of the strips K are provided with narrow portions '32 adapted to fit within the slots 30. Soldering or welding may be employed to fix the narrow portions 32 of the strips K' within "the slots 30 of the condenser terminals 24.

It will, of course, be apparent that, if desired, 'thesupport H may beformed'of the same moldable plastic material as is the main frame A and may be formed integrallytlierewith in asing1e 'molding operation. The lower ends 34 of the strips K may in turn be apertured as at 36 to facilitate connection thereto of wires from other parts'ofthe'radio apparatus.

A portion of each of the stripsK between'the condenser terminals"?! and its lower end 34 is provided with a projecting connection tab38 which for convenience of manufacture may be punched directly from the stripK. "These'tabs "38 provide an exceedingly convenientmeans'ifor electrically connecting the'free ends 26 and' ffi' of the coils F and F to their respective con densers. When the cores G and G"'with the coils F and'F already wound thereon areinsertedinto the passage E and'securedtherein, the free' ends,

""26 and 26 of each of the coils may be inserted between the appropriate tabs38 and" the strips "K; the projecting wire ends may be severed by In order to retain the strips K in fixed spatial relationship with the remainder of theassembly, "and particularly with the coils F andF', feet-L and L are provided on the free ends of the parallel legs B and C, these feetpreferably projecting substantially at right angles to the legs B and -C and being provided with apertures 40 through which the lower ends of thestripsK freelypass. 'Each of the apertures 40 is-preferably-=disposed opposite and in line with a condenser terminal M -so that when the entire transformerisassembled, the legs B and C, the passage E,the-condenser terminals 24 and the strips Kare all substantially parallel one to the other. By thus fixing the lposition of thestripsKwith respectxto the coils -F and F, notonly is a-"rigidi'fie'dstructure pro-,:-

tluce'd'but the capacitive coupling: effect between each" of the 'coils' F and'F is made: constantirom one transformer unit to another and, sinceiallsof the electrical connections are fixed in position, that coupling efiect will remain the same .for 4a given-unit no matter how roughlythatunitmight 'be handled. I This characteristic exceedingly important when the transformei is employed in a high fidelity transmitteror receiver.

The apertures lfl in the feet L may be elongated as by means of collars 42, thus providing iadditional'support for-the strips K. Iniaddition, 'one or more of thecollars, such-as .collar 42., may difier in 'shapefrom the others (see-Fig. :10 in which" three of the collars 4'2f-are circular-in shape and collar 42 is hexagonal) so as to ensure-,t:zby cooperation with suitably formedsockets inithe base plate of the-radio apparatus with whichzthe unit is used, that the unit is properly .positioned "therein andthat proper external connections are made-thereto. When thecollars 42 areemployed in cooperation with sockets in base plates, :the collars: serve the additional function of providing support for the entirezassembly.

The entire unit is customarily encased inea metallic shield can 44 shown in broken 'lines 'in Fig. 1, the can 44 being provided with a-pair0f apertures 46in registration .with the adjusting screws 2| and 22 of the condensers-J and Juso that those condensers :may convenientlyube adjusted and the resonant circuits .tuned thereby after the transformer :assembly has beenas- 'sembled and installed.

By forming the coil core combination asde- *scribed, by mounting and securingJthe cores G 'ticularly adaptedfor use as an-intermediaterfrequency'transformer in radio receiving and transmitting sets has been'produced' Thistransformer J-iSOf exceedingly small sizesand weight,.the.com- -'ponent parts thereof ma be separatelysfabricated, may be quickly and easily. assembled aan'd therequislte electrical connections may bereadily made.

"The transformer assembly isso designed as to'permit the ready incorporation with thebasic pair of capacitors and inductances which .form the two oscillatory magnetically coupled circuits of various other circuit elements such asiresistors, fixed capacitors, or diode filter units of the type describedand claimed in co-pending application, Serial No. 677,96Lof June'20, 11946,

the invention of Monte Cohenand FrederickG. Webber entitled Electrical Structure, nowPat- -ent No. 2,464,377, March 15,1949. *Fig. llri1l-us- 'trates the employment .of such a diode filter unit -48 in. placeof one of the conductive strips-K,.the

'unit48 incorporating in a single structurenazrespace which would inany event be taken upilby the transformer assembly, itwill be seen that the employment of such units takes up no. additional :space in the radio set, thus enablingsmalbsets to obtain the circuit advantages of larger=and more complicated sets WithOUtan increase in-size.

Moreover, both as applied to the transformer zas- -sembly of Fig. 1 as well as of Fig. 11,- theleads are of minimal length, afactor the importance of which increases as the frequency withwhic Ithe unit-isused increases.

. aaeaose Figs. 8 through illustrate the employment of an auxiliary terminal or 50' particularly adapted for use with the transformer structure as thus far described. Figs. 8 and 9 illustrate one form of this terminal and Figs. 14 and 15 an alternative form. The terminal 58 of Figs. 8 and 9 is formed of non-conductive material and preferably of the same moldable plastic as the main frame A. It comprises a portion 52 receivable within the open end of the passage E, the inner surfaces 54 and 58 of the feet L and L being concavely cut out corresponding to the inner surfaces 8 and II of the legs B and C to accommodate the same, and a stop portion 58 adapted to limit the degree of entry of the member 50 into the passage. Carried by the non-conductive member 50 is a conductive connector 60 which may be formed of sheet metal similar to that of which the strips K are made. The connector 60 passes through an axial aperture 62 in the member 5| and is here shown as bent into L-shape so as to have a portion 64 adapted to project parallel to the feet L and L and to have another portion 68 adapted to project downwardly at right angles thereto and parallel to the portion 34 of the strips K when the auxiliary terminal 50 is received in position within the passage E. Each of the portions 64 and 66 is apertured at 68 and 10, respectively, to facilitate the connection of wires thereto. The connector 60 may be secured within the terminal 50 by suitably deforming the moldable plastic of which the terminal 50 is formed in a manner similar to that employed to produce the tabs l2 on the main frame A.

It has been found that employment of the terminal 50 involves difficulties in making connection with the portion 64, and particularly that short circuits are very apt to obtain. Accordingly, it has been found desirable in many instances to vary the design of this terminal to that shown by the terminal 50' of Figs. 14 and 15. Two differences may be noted between the two terminals. In the first place, the portion 84 of the connector 60 is received within a groove in the body thereof so that the surface 61 of the portion 64 does not project above the corresponding surface of the terminal 50'.

A second and more important difference, inasmuch as it has been found to materially facilitate the attaining of proper connections, is that the end 69 of the portion 64 is bent to a position approximately parallel to the portion 66, so that when the terminal 50 is received in position within the passage E, the portion 69 of the connector 60 will also be substantiall parallel to the conductive strips K.

In the arrangement illustrated in Fig. 11 5|" represents a still further modified form of auxiliary terminal in which the portion 69 of the connector 60 is extended upwardly a distance sufficient to make direct connection with a central terminal on the filter unit 48. In that figure the leads 72, T4, and 16 represent the connections illustrated in Fig. 12. As there illustrated, the lead 16 itself passes through the aperture 40 in the foot L. It will be noted that each of these apertures 40 is so shaped as to permit either the flat conductive strip K (see Fig. 10) or one or more round wire leads (see Figs. 11 and 12) to pass therethrough, thus facilitating the flexibility of adaptation of a single transformer structure to widely varying applications. Such standardization of structure accompanied by such fiexibility of use represents a considerable advantage over prior art devices. Even when leads are used,

'as in the case of Figs. 11 and 12, the apertures ll rigidly space and position those leads and thus retain the desirable constant capacitance characteristics above described.

The arrangement of Figs. 11, 12 and 13 illustrate the employment of a by-pass filter composed of the resistor and the capacitors 82 and 84 which may be used to provide an effective radio frequency by-pass to ground when employed with intermediate frequency transformers.

It will thus be apparent that the structure we have invented is not only well adapted to the formation of a light-weight transformer of small size but is also well adapted for the incorporatio therewith of various other circuit elements as circuit design ma dictate and this without any attendant increase in space consumption. By reason particularly of the construction of the conductive strips K and the connection tabs 38 thereon, electrical connection between these auxiliary units and the elements of the transformer may be quickly and conveniently made in the same way that the free ends 25 and 26' of the coils F and F are connected into the circuit.

It will be apparent that many changes may be made in the detailed design of this transformer without departing from the spirit of the invention as defined in the following claims.

We claim:

1. An intermediate transformer assembly comprising a substantially U-shaped main frame of non-conductive material including legs and a cross-piece, said legs being deformable at any desired point therealong and defining an openended passage therebetween, a non-conductive support on the cross-piece of said main frame and carrying at least one condenser, a pair of cores on which coils are wound movable in said passage parallel to said legs to any desired adjusted position relative to one another, said cores being securable in said adjusted positions by direct engagement with deformations formed in said legs after said cores have been positioned.

2. In the assembly of claim 1, condenser terminals electrically connected to the plates of said condenser and projecting from said support toward said main frame, feet on the end of said legs, said feet extending substantially perpendicularly with respect to the plane of the U so as not to close the open end of said passage, apertures in said feet opposite said condenser terminals, and a conductive strip defining a part of the electrical connections, said strip passing through an aperture in said feet and connected to the corresponding condenser terminal.

3. In the assembly of claim 1, condenser terminals electrically connected to the plates of said condenser and projecting from said support toward said main frame, feet on the end of said legs, said feet extending substantially perpendicu- V larly with respect to the plane of the U so as not to close the open end of said passage, apertures in said feet opposite said condenser terminals,

and a conductive strip defining a part of the electrical connections, said strip passing through an aperture in said feet and connected to the corresponding condenser terminal, the portion of said strip between said condenser terminal and said aperture having a connection tab projecting therefrom at an appropriate position along its length for receiving the free end of a coil.

4. An intermediate frequency transformer assembly comprising a substantially U -shaped main frame of non-conductive material including legs and-1a cross-"piece, said legs Ldefining anopenended :passage therebetween, a non-conductive support attached to .or formed with the crosspiecerof said main frame "and carryingna' pair of condensers-condenser terminals attached to the plates-of said Jcondensers and projecting from SfijdvSllPDOIt toward said mainframe, non-conductive feet onthe endsi ofsaid legs, each'of said feet. extending to both sides of its leg and-providedwith apertures opposite'said condenser terminalaa pair of cores on which coils are wound separated from one anotherand secured against axial movement in saidpassage' by direct engagement with said legs, and electrical connections between said coils and said condensers including fourzconductive strips each freely passing through oneof theapertures in said feet and connected to the corresponding condenser terminal.

.5. An' intermediate frequency transformer assembly comprising asubstantially U-shaped'main framexof non-conductive material including legs and across-piece, saidlegs defining an openended passage therebetween, a non-conductive support on the crosspiece or said main frame. and carrying a pairof condensers, condenser termina'ls. attached tothe platesof said condensers and projecting from said supporttoward said main frame, non-conductive feet onithe endsofsaid legs,aeach of said feet extending to both sides of itsialeg and provided with apertures opposite said condenser terminals, a pair 'of. magnetic cores on which icoilsare wound separated from one another and secured against axial movement in said passage bytdirect engagement with said legs, and electrical connectionsbetween said coils and said condensers including four conductive strips each freely passing through oneof the apertures in said feet an'd' connected to the corresponding condenser terminal, the portion of each of said strips between said condenserterminal and said aperture'hav-ing a connection tab projecting therefrom at an appropriate position along its length for receiving the free end of a coil.

6. An intermediate frequency transformer assembly comprising a substantially u-shaped main frame of non-conductive material including legs and a cross-piece, said legs being concave on their interior surfaces and defining an openended passage therebetween, a non-conductive support on the cross-piece of said main frame and carrying a pair of condensers, condenser terminals attached to the plates of said condensersand projecting from said support toward said main frame, non-conductive feet on the ends of said legs, each of said feet extending to both sides of itsilegfland" provided with apertures opposite said condenser terminals, a pair of cylindrical magnetic cores on whichcoils are wound separated from one another and secured against axial movement in said'passagebydirect engagement with saidlegs'andelectrical connections between said coils and said condensers including four conductiveistripseach freely passing through one of the aperturesinsaid feet and connected to the corresponding condenser "terminal, the portion of each of said strips between said condenser terminal and said aperture having a connection tab projecting therefrom at 1 an appropriate position along its length for receiving the free end of a coil.

'7. In combination with the transformer assembly of claim 1, an auxiliary terminal comprising a non-conductive member having a cylindrical portion receivable in the open end of the passage between said legs and a stop portion 10' adapted to limit the degree of entry of said member into said passage and a conductive connector carried by said member and having aportion adapted to project below said legs and another portion adapted to project above said terminal.

8. In combination with the transformer assembly of claim 6, an auxiliary terminal comprising a non-conductive member having acylindrical-portion-receivable within the open end of the passage between said legs and a stop portion adapted to limit the degree of entry of saidcylindrical portion into said passage, and a conductive connector carried by said member and having a portion adapted to project below said legs and anotherportion adapted to project above said terminal.

9. The assembly of claim 4, in which the condenser terminals are slotted and in which said conductivestrips are provided at their ends connectedto said condenser terminals with anarrow portion adapted to enter said slots.

10. Anintermediate frequency transformer assembly comprisinga substantially U -shaped main frame ofnon-conduct-ive material including legs and across-piece, said legs defining an openended passage therebetween, a non-conductive support on the cross-piece of said main frame and carrying at least one condenser, cores on which coils are wound secured against axial movement in said passage by direct engagement with said legs, condenser terminals electrically connected to the plates of said condenser and projecting from said support toward said main frame, feet on the end of said legs, said-feet extending substantially perpendicularly with respect to the plane of the U so as ,not to close'the open end of said passage, apertures in saidfeetopposite said condenser terminals, and electrical connections betweensaid coils and said condensers including a conductive strip passing through an aperture in said. feet and connected to. the corresponding condenser terminal.

11. An intermediate frequency transformerassembly comprising-a substantially U -shaped main frame opinion-conductive material including legs and across-piece, said legsdefining an openended passage therebetween, a non-conductive support on the crossepiece-of said main frame and carrying atleast one condenser, coreson which coils are wound secured against axial movement insaid passage by directengagement with said legs, condenser terminals electrically connected to the platesof said condenser and projecting fromsaid support toward said'main frame, feet x on the end of said legs, said feet extendingsubstantially perpendicularly with respect to the plane of'the .U so asnot'to'close the open end of said passage, apertures in said feet opposite said condenserterminals, and electrical connections between'saidcoils-and said condenser'ineluding a conductive strip passing through an aperture in said feet and connected to thecorresponding condenser terminal, the portion of said'strip between said condenser terminal and said aperture having a connection tab projecting therefrom at an appropriate position along its length for receiving the'free end of' a coil.

12. An intermediate frequency'transformer assembly comprising a substantially U-shapedmain frame of molded non-conductive distortable plastic material including legs and a cross-piece, said legs being deformable at any desired position therealong and defining an open-ended passage therebetween, a non-conductive support on the cross-piece of said main frame and carrying at least one condenser, a pair of cores on which coils are wound movable in said passage parallel to said legs to any desired adjusted position relative to one another prior to deformation of said legs, said cores being securable in said adjusted positions by direct engagement with deformations formed in said legs after said cores have been positioned.

13. A transformer assembly comprising a substantially U-shaped main frame of molded nonconductive distortable plastic material including legs and a cross-piece, said legs being deformable at any desired point therealong and defining an open-ended passage therebetween, and a pair of cores on which coils are wound movable in said passage parallel to said legs to any desired adjusted position prior to deformation of said legs, said cores being securable in said adjusted positions by direct engagement with deformations formed in said legs after said cores have been positioned.

14. A transformer assembly comprising a main frame of non-conductive deformable material having at least two parallel legs defining an open ended passage therebetween, said legs being deformable at any desired point therealong, and a plurality of electrical components operatively connected to and supported by said frame, said components including a core on which a coil is wound movable in said passage parallel to said legs to any desired adjusted position prior to deformation of said legs, said core being securable in said adjusted position by direct engagement with deformations formed in said legs after said core has been positioned, and an auxiliary terminal comprising a non-conductive member receivable in the open end of the passage between said legs and a conductive connector carried by said member and adapted to be electrically connected to One of said electrical components.

15. A transformer assembly comprising a main frame of non-conductive deformable material having at least two parallel legs defining an open ended passage there-between, said legs being deformable at any desired point therealong, and a plurality of electrical components operatively connected to and supported by said frame, said components including a core on which a coil is wound movable in said passage parallel to said legs to any desired adjusted position prior to deformation of said legs, said core being securable in said adjusted position by direct engagement with deformations formed in said legs after said core has been positioned, and an auxiliary terminal comprising a non-conductive member receivable in the open end of the passage between said legs and a conductive carrier carried by said member and having a portion projecting below said legs and another portion projecting above said member, said other portion being adapted to be electrically connected to one of said electrical components.

16. A transformer assembly comprising a main frame of non-conductive deformable material having at least two parallel legs defining an open ended passage there-between, said legs being deformable at any desired point therealong, and a plurality of electrical components operatively connected to and supported by said frame, said components including a core on which a coil is wound movable in said passage parallel to said legs to any desired adjusted position prior to deformation of said legs, said core being securable in said adjusted position by direct engagement with deformations formed in said legs after said core has been positioned, and an auxiliary terminal comprising a non-conductive member having a portion receivable in the open end of the passage between said legs and a stop portion adapted to limit the degree of entry of said member into said passage, and a conductive connector carried by said member and adapted to be electrically connected to one of said electrical components.

17. A transformer assembly comprising a main frame of non-conductive deformable material having at least two parallel legs defining an open ended passage therebetween, said legs being deformable at any desired point therealong, and a plurality of electrical components operatively connected to and supported by said frame, said components including a core on which a coil is wound movable in said passage parallel to said legs to any desired adjusted position prior to deformation of said legs, said core being securable in said adjusted position by direct engagement with deformations formed in said legs after said core has been positioned, and an auxiliary terminal comprising a non-conductive member having a portion receivable in theopen end of the passage between said legs and a stop portion adapted to limit the degree of entry of said member into said passage, and a conductive connector carried by said member and having a portion projecting below said legs and another portion projecting above said member, said other portion being adapted to be electrically connected to one of said electrical components.

HOWARD J. BENNER. ALLAN M. HADLEY.

REFERENCES CITED The following references are of record in the file of this patent:

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